Purpose <p>To evaluate the impact of fibrinogen monitoring on bleeding complications and rates of premature tPA cessation in patients undergoing catheter-directed thrombolysis (CDT). We hypothesize that routine fibrinogen monitoring does not lower bleeding complications but may result in more cases of incomplete thrombolysis due to premature tPA termination.</p> Methods <p>This single-institution retrospective study examined patients who underwent CDT for arterial, venous, or pulmonary thrombosis from 2011 to 2023. Rates of significant hemorrhages and premature tPA cessation were compared in patients with and without routine fibrinogen monitoring. Premature tPA cessation was defined as termination of thrombolytic infusion prior to the planned treatment endpoint due to low fibrinogen levels or clinical bleeding concerns.</p> Results <p>A total of 355 CDT procedures met inclusion criteria, including 225 cases without routine monitoring (control group) and 130 with routine fibrinogen monitoring. Bleeding rates were similar between groups (3.55% vs. 3.07%, <i>p</i> = 1.00). However, premature tPA cessation occurred significantly more frequently in the fibrinogen monitoring cohort (17.5% vs. 1.78%, <i>p</i> &lt; 0.001). Among cases with premature tPA cessation, residual thrombus requiring adjunctive interventions was common.</p> Conclusion <p>This study demonstrated that routine fibrinogen monitoring was not associated with significantly reduced bleeding complications, but is linked to higher rates of premature tPA cessation in stable patients, which may contribute to incomplete thrombolysis and increased need for adjunctive interventions.</p> Graphical Abstract <p></p>